Le>
>> >>
>>>I'm looking for a waveform generator that outputs two sine waves of
>>>the same frequency with 90 degree phase difference (sine and cosine).
>>>I need a variable frequency between 0.05 Hz and 10 Hz. Is there an
>>>analog design that uses a single potentiometer or perhaps is voltage
>>>controlled ? Low distortion is not a requirement.
>>>
>>>Steve
>>
>>
>> I've used a software DDS running on an MCU with a DAC for that sort of
>> thing. It's much easer to design and build than any analogue circuit.
>>
>> Leon
>>
> Digital, NOT analog.
There are hybrid approaches, DDS clock / reference and two wide range (200:1 frequency range) PLLs.